He is standing to represent Rhode Island's 1st Congressional District. The seat will become vacant because Rep. Patrick Kennedy has said he will stand down.

Cicilline succeeded against former state party Chairman Bill Lynch, businessman Anthony Gemma and state Rep. David Segal to win the nomination.

The Providence mayor has been supported by gay group Human Rights Campaign and raised more funds than any other candidate.

HRC president Joe Solmonese said: "We are thrilled that David Cicilline has advanced to the general election and look forward to working with him to ensure Rhode Island's first district is represented by a fair-minded legislator.

"He has proven himself as a state senator and strong mayor and will no doubt be an active and effective Congressman in promoting equality for all people."

Currently, only three of the more than 500 Congressmen are gay: Barney Frank of Massachusetts, Tammy Baldwin of Wisconsin and Jared Polis of Colorado.